1. Field of the Invention
The present invention relates generally to data processing systems. More specifically, the present invention relates to a computer implemented method, computer program product, and a system for computing path oriented statistics and integrating downstream performance and resource usage statistics into load balancing weights.
2. Description of the Related Art
In datacenter environments, many copies of servicing components, such as application servers, http servers, and so forth, are used to handle increasingly large loads. In these cases, incoming service requests typically go to a load balancer to be directed to the appropriate servicing component. Modern advances in technology, like the Server/Application State Protocol (SASP), have allowed load balancers to receive recommendations, in the form of numerical weights, as to the best distribution of the incoming requests. Previous techniques for dynamically calculating these weights involve using application performance and usage statistics from the set of components that are one hop away from the load balancer. Components that are one hop away are the components that the load balancer sends the incoming connections to directly.
Many of today's applications require transactions to go through several components before the transactions may be completed. If complications arise in any of the downstream components, the most important statistical information for the weight computation may be the information from the downstream components where the complication is arising. A downstream component is a component touched by a transaction after the transaction touches the first component. Therefore, it would be advantageous to provide a way of computing applications or system statistics for the entire transaction path. These path-oriented statistics can then be used in any load balancing algorithm that uses application or system statistics for computing load balancing weights.
Patent application number US 2005-0120095 A1 entitled, “Apparatus and Method for Determining Load Balancing Weights Using Application Instance Statistical Information,” published Jun. 2, 2005 addresses a complimentary issue. The US 2005-0120095 A1 application describes a method for generating load balancing weights using application statistics. However, the method described in the US 2005-0120095 A1 application only computes the load balancing weight based on the statistics from a single application, regardless of the number of applications involved in a transaction or of the path the transaction follows. The US 2005-0120095 A1 application does not address the problem of calculating path-oriented statistics. However, path-oriented statistics may be used in a load balancing weight generation algorithm like that described in US 2005-0120095 A1 application.